Jenkins pipeline "waitUntil" - change delay between attempts - jenkins

Question

We use a Jenkins pipeline for our builds and tests. After the build, we run automated tests on several measurement devices.
For a better overview about the needed testing time, I created a test stage which is periodically checking the status of the tests. When all tests are finished, the pipeline is done. I use the "waitUntil" implementation of Jenkins pipeline for this functionality.
My problem is: The pause between the attemps gets more and more after every try. This is a quite good idea. BUT: After a while, the pause between the attemps gets up to 16 hours and more. This value is too high for my needs because I want to know the needed test time exactly.
My question is: Does anyone know a way to change this behaviour of "waitUntil"?
I know I could use a "while" loop but I would prefer to solve this using "waitUntil".
stage ">>> Waiting for testruns"
waitUntil {
sleep(10)
return(checkIfTestsAreFinished())
}

Answer 1

New versions of Jenkins have capped this to never go over 15 seconds (see https://issues.jenkins-ci.org/browse/JENKINS-34554 ).

Answer 2

In waitUntil, if the processing in the block returns false, then the waitUntil step waits a bit longer and tries again. “a bit longer” means, a 0.25 second wait time. If it needs to loop again, it multiplies that by a factor of 1.2 to get 0.3 seconds for the next wait cycle. On each succeeding cycle, the last wait time is multiplied again by 1.2 to get the time to wait. So, the sequence goes as 0.25, 0.3, 0.36, 0.43, 0.51... until 15 secs(as it is mentioned in one of the answers below, Jenkins solved it).
See the image below:
If you are using older Jenkins version then possible solution could be to use timeout
timeout(time: 1, unit: 'HOURS'){
// you can change format in seconds, minutes, hours
// you can decide your know timeout limit.
waitUntil {
try {
//sleep(10)// you don't need this
return(checkIfTestsAreFinished())
} catch (exception) {
return false
}
}//waituntil
}//timeout
Please note the behavior is from Jenkins LTS 2.235.3.

Answer 3

Jenkins command waitUntil is not supposed to launch something synchronously.
To know the required time you must add a timestamp into the test output parse it and calc separately.